Neil Young’s seemingly bottomless archive yields Sugar Mountain — Live at Canterbury House 1968, a pair of acoustic concerts recorded soon after he left Buffalo Springfield. His meandering monologues contrast with the top-notch if uniformly pensive songs. ”Mr. Soul” and ”Expecting to Fly” reprise the then-recent past, while tracks like ”The Loner,” the exquisite ”Birds,” and the bittersweet title song provide a live demo tape of his immediate future. B+